This invention relates to a wear surface, hard facing and process. More specifically, but not by way of limitation, this invention relates to a bearing used in surface facilities as well as down hole tools situated in a well bore, and a process for manufacturing the bearing.
In the search for oil and gas, operators find it necessary to drill with a down hole tool that utilizes a down hole motor. As those of ordinary skill in the art will appreciate, the down hole motor includes a stationary housing and a concentrically disposed drive shaft, wherein the drive shaft has attached a bit means for boring a bore hole. The mandrel is rotated while concentrically located within the stationary housing. The friction created by the rotation of the stationary housing relative to the rotating mandrel can cause significant problems including wear, deformation and over-heating. Bearings have been developed for use in these tools. Prior art remedies include use of a coating process about the drive shaft, as well as the inner diameter of the stationary housing. Prior art techniques further include use of carbide inserts as well using standard roller and ball bearing technology.
At least two prior art coating processes are available, namely the adhesion process and the fusion process. Generally, the fusion process is more reliable than the adhesion process because when fusion occurs, the coating material melts into the carrier metal. One inexpensive adhesion process is spray coating, wherein the coating material bonds to the carrier material only due to adhesion force. There are several commercial adhesion process applications available.
As those of ordinary skill in the art will recognize, the fusion process requires significant temperature to melt the surface of materials. Thus, large spray heads and large heating sources are required, and wherein these space limitations make it very impractical for the fusion of inner diameter surfaces such as required for the down hole motors.
As noted earlier, solid carbide and carbide tiles (or splits, or balls) are also available for bearings, and wherein the solid carbide and/or carbide tiles are compressed or glued into the inner diameter of a radial bearing. The solid carbide is very sensitive to shock loading, and the filler matrix of the tiles is very sensitive to temperature, which are both problematic.
Therefore, there is a need for a bearing that can withstand the high temperature and shock loading of down hole applications. There is also a need for an efficient and economical bearing for use with surface equipment and down hole tools. Further, there is a need for a radial bearing used in mud motors. These and many other needs will be met by a reading of the following disclosure.